Ink jet printer having a thermal actuator comprising an external coil spring

ABSTRACT

In accordance with a first aspect of the present invention, there is provided a thermal actuator activated by conductive heating of an electrically conductive material, the actuator including: a first non-conductive strip of material attached to a substrate at a first end of the strip and adapted to apply a force to a load at a second end of the strip; a second conductive strip of material formed along one side of the first strip, the second conductive strip including a first wire strip running from substantially the first end to the second end and a second wire strip running from substantially the second end to the fist end, the wire strips being joined together at the second end so as to form a circuit, the wire strips being further connected to a controlled power supply at the first end such that activation of the controlled power supply causes heating of the conductive material so as to actuate the thermal actuator thereby applying a force to the load. Preferably, the first strip is in the form of a coil and the second conductive material is formed along a radial inner surface.

CROSS REFERENCES TO RELATED APPLICATIONS

The following Australian provisional patent applications are hereby incorporated by cross-reference. For the purposes of location and identification, U.S. patent applications identified by their U.S. patent application serial numbers (U.S.S.N.) are listed alongside the Australian applications from which the US patent applications claim the right of priority.

U.S. PATENT APPLICATION (CLAIMING RIGHT OF CROSSS-REFERENCED PRIORITY FROM AUSTRALIAN AUSTRALIAN PROVISIONAL PROVISIONAL PATENT No. APPLICATION) DOCKET No. PO7991 09/113,060 ART01  PO8505 09/113.070 ART02  PO7988 09/113.073 ART03  PO9395 09/112,748 ART04  PO8017 09/112,747 ART06  PO8014 09/112,776 ART07  PO8025 09/112.750 ART08  PO8032 09/112,746 ART09  PO7999 09/112,743 ART10 PO7998 09/112,742 ART11 PO8031 09/112,741 ART12 PO8030 09/112,740 ART13 PO7997 09/112,739 ART15 PO7979 09/113,053 ART16 PO8015 09/112,738 ART17 PO7978 09/113,067 ART18 PO7982 09/113,063 ART19 PO7989 09/113,069 ART20 PO8019 09/112,744 ART21 PO7980 09/113,058 ART22 PO8018 09/112,777 ART24 PO7938 09/113,224 ART25 PO8016 09/112,804 ART26 PO8024 09/112,805 ART27 PO7940 09/113,072 ART28 PO7939 09/112,785 ART29 PO8501 09/112,797 ART30 PO8500 09/112,796 ART31 PO7987 09/113,071 ART32 PO8022 09/112,824 ART33 PO8497 09/113,090 ART34 PO8020 09/112,823 ART38 PO8023 09/113,222 ART39 PO8504 09/112,786 ART42 PO8000 09/113,051 ART43 PO7977 09/112,782 ART44 PO7934 09/113,056 ART45 PO7990 09/113,059 ART46 PO8499 09/113,091 ART47 PO8502 09/112,753 ART48 PO7981 09/113,055 ART50 PO7986 09/113,057 ART51 PO7983 09/113,054 ART52 PO8026 09/112,752 ART53 PO8027 09/112,759 ART54 PO8028 09/112,757 ART56 PO9394 09/112,758 ART57 PO9396 09/113,107 ART58 PO9397 09/112,829 ART59 PO9398 09/112,792 ART60 PO9399 09/112,791 ART61 PO9400 09/112,790 ART62 PO9401 09/112,789 ART63 PO9402 09/112,788 ART64 PO9403 09/112,795 ART65 PO9405 09/112,749 ART66 PP0959 09/112,784 ART68 PP1397 09/112,783 ART69 PP2370 09/112,781 DOT01 PP2371 09/113,052 DOT02 PO8003 09/112,834 Fluid01 PO8005 09/113,103 Fluid02 PO9404 09/113,101 Fluid03 PO8066 09/112,751 IJ01  PO8072 09/112,787 IJ02  PO8040 09/112,802 IJ03  PO8071 09/112,803 IJ04  PO8047 09/113,097 IJ05  PO8035 09/113,099 IJ06  PO8044 09/113,084 IJ07  PO8063 09/113,066 IJ08  PO8057 09/112,778 IJ09  PO8056 09/112,779 IJ10 PO8069 09/113,077 IJ11 PO8049 09/113,061 IJ12 PO8036 09/112,818 IJ13 PO8048 09/112,816 IJ14 PO8070 09/112,772 IJ15 PO8067 09/112,819 IJ16 PO8001 09/112,815 IJ17 PO8038 09/113,096 IJ18 PO8033 09/113,068 IJ19 PO8002 09/113,095 IJ20 PO8068 09/112,808 IJ21 PO8062 09/112,809 IJ22 PO8034 09/112,780 IJ23 PO8039 09/113,083 IJ24 PO8041 09/113,121 IJ25 PO8004 09/113,122 IJ26 PO8037 09/112,793 IJ27 PO8043 09/112,794 IJ28 PO8042 09/113,128 IJ29 PO8064 09/113,127 IJ30 PO9389 09/112,756 IJ31 PO9391 09/112,755 IJ32 PP0888 09/112,754 IJ33 PP0891 09/112,811 IJ34 PP0890 09/112,812 IJ35 PP0873 09/112,813 IJ36 PP0993 09/112,814 IJ37 PP0890 09/112,764 IJ38 PP1398 09/112,765 IJ39 PP2592 09/112,767 IJ40 PP2593 09/112,768 IJ41 PP3991 09/112,807 IJ42 PP3987 09/112,806 IJ43 PP3985 09/112,820 IJ44 PP3983 09/112,821 IJ45 PO7935 09/112,822 IJM01  PO7936 09/112,825 IJM02  PO7937 09/112,826 IJM03  PO8061 09/112,827 IJM04  PO8054 09/112,828 IJM05  PO8065 09/113,111 IJM06  PO8055 09/113,108 IJM07  PO8053 09/113,109 IJM08  PO8078 09/113,123 IJM09  PO7933 09/113,114 IJM10 PO7950 09/113,115 IJM11 PO7949 09/113,129 IJM12 PO8060 09/113,124 IJM13 PO8059 09/113,125 IJM14 PO8073 09/113,126 IJM15 PO8076 09/113,119 IJM16 PO8075 09/113,120 IJM17 PO8079 09/113,221 IJM18 PO8050 09/113,116 IJM19 PO8052 09/113,118 IJM20 PO7948 09/113,117 IJM21 PO7951 09/113,113 IJM22 PO8074 09/113,130 IJM23 PO7941 09/113,110 IJM24 PO8077 09/113,112 IJM25 PO8058 09/113,087 IJM26 PO8051 09/113,074 IJM27 PO8045 09/113,089 IJM28 PO7952 09/113,088 IJM29 PO8046 09/112,771 IJM30 PO9390 09/112,769 IJM31 PO9392 09/112,770 IJM32 PP0889 09/112,798 IJM35 PP0887 09/112,801 IJM36 PP0882 09/112,800 IJM37 PP0874 09/112,799 IJM38 PP1396 09/113,098 IJM39 PP3989 09/112,833 IJM40 PP2591 09/112,832 IJM41 PP3990 09/112,831 IJM42 PP3986 09/112,830 IJM43 PP3984 09/112,836 IJM44 PP3982 09/112,835 IJM45 PP0895 09/113,102 IR01  PP0870 09/113,106 IR02  PP0869 09/113,105 IR04  PP0887 09/113,104 IR05  PP0885 09/112,810 IR06  PP0884 09/112,766 IR10 PP0886 09/113,085 IR12 PP0871 09/113,086 IR13 PP0876 09/113,094 IR14 PP0877 09/112,760 IR16 PP0878 09/112,773 IR17 PP0879 09/112,774 IR18 PP0883 09/112,775 IR19 PP0880 09/112,745 IR20 PP0881 09/113,092 IR21 PO8006 09/113,100 MEMS02 PO8007 09/113,093 MEMS03 PO8008 09/113,062 MEMS04 PO8010 09/113,064 MEMS05 PO8011 09/113,082 MEMS06 PO7947 09/113,081 MEMS07 PO7944 09/113,080 MEMS09 PO7946 09/113,079  MEMS10 PO9393 09/113,065  MEMS11 PP0875 09/113,078  MEMS12 PP0894 09/113,075  MEMS13

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

FIELD OF THE INVENTION

The present invention relates to the field ink jet printers and in particular, discloses an ink jet printer having a thermal actuator comprising an external coil spring of a unique construction.

BACKGROUND OF THE INVENTION

Many different types of printing have been invented, a large number of which are presently in use. The known forms of print have a variety of methods for marking the print media with a relevant marking media. Commonly used forms of printing include offset printing, laser printing and copying devices, dot matrix type impact printers, thermal paper printers, film recorders, thermal wax printers, dye sublimation printers and ink jet printers both of the drop on demand and continuous flow type. Each type of printer has its own advantages and problems when considering cost, speed, quality, reliability, simplicity of construction and operation etc.

In recent years, the field of ink jet printing, wherein each individual pixel of ink is derived from one or more ink nozzles has become increasingly popular primarily due to its inexpensive and versatile nature.

Many different techniques on ink jet printing have been invented. For a survey of the field, reference is made to an article by J Moore, “Non-Impact Printing: Introduction and Historical Perspective”, Output Hard Copy Devices, Editors R Dubeck and S Sherr, pages 207-220 (1988).

Ink Jet printers themselves come in many different types. The utilization of a continuous stream ink in ink jet printing appears to date back to at least 1929 wherein U.S. Pat. No. 1,941,001 by Hansell discloses a simple form of continuous stream electro-static ink jet printing.

U.S. Pat. No. 3,596,275 by Sweet also discloses a process of a continuous ink jet printing including the step wherein the ink jet stream is modulated by a high frequency electro-static field so as to cause drop separation. This technique is still utilized by several manufacturers including Elmjet and Scitex (see also U.S. Pat. No. 3,373,437 by Sweet et al)

Piezoelectric ink jet printers are also one form of commonly utilized ink jet printing device. Piezoelectric systems are disclosed by Kyser et. al. in U.S. Pat. No. 3,946,398 (1970) which utilizes a diaphragm mode of operation, by Zolten in U.S. Pat. No. 3,683,212 (1970) which discloses a squeeze mode of operation of a piezoelectric crystal, Stemme in U.S. Pat. No. 3,747,120 (1972) discloses a bend mode of piezoelectric operation, Howkins in U.S. Pat. No. 4,459,601 discloses a piezoelectric push mode actuation of the ink jet stream and Fischbeck in U.S. Pat. No. 4,584,590 which discloses a sheer mode type of piezoelectric transducer element.

Recently, thermal ink jet printing has become an extremely popular form of ink jet printing. The ink jet printing techniques include those disclosed by Endo et al in GB 2007162 (1979) and Vaught et al in U.S. Pat. No. 4,490,728. Both the aforementioned references disclosed ink jet printing techniques rely upon the activation of an electrothermal actuator which results in the creation of a bubble in a constricted space, such as a nozzle, which thereby causes the ejection of ink from an aperture connected to the confined space onto a relevant print media. Printing devices utilizing the electro-thermal actuator are manufactured by manufacturers such as Canon and Hewlett Packard.

As can be seen from the foregoing, many different types of printing technologies are available. Ideally, a printing technology should have a number of desirable attributes. These include inexpensive construction and operation, high speed operation, safe and continuous long term operation etc. Each technology may have its own advantages and disadvantages in the areas of cost, speed, quality, reliability, power usage, simplicity of construction operation, durability and consumables.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide for an inkjet printing device having a unique form of actuator suitably used for use in the ejection of ink.

In accordance with a first aspect of the present invention, there is provided a thermal actuator activated by means of conductive heating of an electrically conductive material, the actuator comprising: a first non-conductive strip of material attached to a substrate at a first end of the strip and adapted to apply a force to a load at a second end of the strip; a second conductive strip of material formed along one side of the first strip, the second conductive strip including a first wire strip running from substantially the first end to the second end and a second wire strip running from substantially the second end to the first end, the wire strips being joined together at the second end so as to form a circuit, the wire strips being further connected to a controlled power supply at the first end such that activation of the controlled power supply causes heating of the conductive material so as to actuate the thermal actuator thereby applying a force to the load.

Preferably, the first strip is in the form of a coil and the second conductive material is formed along a radially inner surface of the strip. The first wire and the second wire can be electrically insulated from one another by a layer of the first non-conductive material. Preferably, the second conductive material comprises a material having a high Young's modulus and the first non-conductive strip is substantially thicker than the second conductive material. The substrate can comprise an electronic circuitry layer of a silicon wafer, the second conductive material can comprise substantially titanium diboride and the first non-conductive material can comprise substantially glass.

The actuator can be interconnected through a slot in a nozzle chamber to a paddle type device, the nozzle chamber being filled with ink and the actuator being activated to eject ink from a port defined in one wall of the nozzle chamber.

In accordance with a second aspect of the present invention, there is provided an ink jet printer having a series of ink ejection nozzle chambers each containing: an ink ejection port defined in one wall of the chamber for the ejection of ink therefrom; a paddle within the chamber, actuated by an actuator for the ejection of ink from the nozzle chamber via the ink ejection port; a slot defined in a second wall thereof for the communication with the paddle of an actuator device; a thermal actuator activated by means of conductive heating of an electrically conductive material, the actuator comprising a first non-conductive strip of material attached to a substrate at a first end of the strip and adapted to apply a force to a load at a second end of the strip; a second conductive strip of material formed along one side of the first strip, the second conductive strip including a first wire strip running from substantially the first end to the second end and a second wire strip running from substantially the second end to the first end, the wire strips being joined together at the second end so as to form a circuit, the wire strips being further connected to a controlled power supply at the first end such that activation of the controlled power supply causes heating of the conductive material so as to actuate the thermal actuator thereby applying a force to the load.

The nozzle chambers can be formed on a silicon wafer and include a series of ink supply channels etched through the wafer for the supply of ink to the nozzle chamber.

BRIEF DESCRIPTION OF THE DRAWINGS

Notwithstanding any other forms which may fall within the scope of the present invention, preferred forms of the invention will now be described, by way of example only, with reference to the accompanying drawings in which:

FIG. 1 illustrates a single ink ejection mechanism as constructed in accordance with the principles of the preferred embodiment;

FIG. 2 is a section through the line II—II of the actuator arm of FIG. 1;

FIGS. 3-5 illustrate the basic operation of the ink ejection mechanism of the preferred embodiment;

FIG. 6 is an exploded perspective view of an ink ejection mechanism.

FIG. 7 provides a legend of the materials indicated in FIGS. 8 to 22; and

FIG. 8 to FIG. 22 illustrate sectional views of the manufacturing steps in one form of construction of an ink jet printhead nozzle.

DESCRIPTION OF PREFERRED AND OTHER EMBODIMENTS

In the preferred embodiment, there is provided an inkjet printer having a series of ink ejection mechanisms wherein each ink ejection mechanism includes a paddle actuated by a coil actuator, the coil spring actuator having a unique cross section so as to provide for efficient actuation as a coiled thermal actuator.

Turning initially to FIG. 1, there is illustrated a single ink ejection mechanism 1 constructed in accordance with the principles of the preferred embodiment. The ink ejection mechanism 1 includes a chamber 2 having a rim 3. The chamber 2 is normally filled with ink which bulges out around a surface having a border along the edge of rim 3, the ink being retained within the chamber 2 by means of surface tension around the rim 3. Outside of the chamber 2 is located a thermal actuator device 5. The thermal actuator device 5 is interconnected via a strut 6 through a hole 7 to a paddle device within the chamber 2. The strut 6 and hole 7 are treated so as to be hydrophobic. Further, the hole 7 is provided in a thin elongated form so that surface tension characteristics also assist in stopping any ink from flowing out of the hole 7.

The thermal actuator device 5 comprises a first arm portion 9 which can be constructed from glass or other suitable material. A second arm portion 10 can be constructed from material such as titanium diboride which has a large Young's modulus or bending strength and hence, when a current is passed through the titanium diboride layer 10, it expands with a predetermined coefficient of thermal expansion. The thin strip 10 has a high Young's modulus or bending strength and therefore the thin strip 10 is able to bend the much thicker strip 9 which has a substantially lower Young's modulus.

Turning to FIG. 2, there is illustrated a cross-section of the arm through the line II—II of FIG. 1 illustrating the structure of the actuator device 5. As described previously, the actuator device 5 includes two titanium diboride portions 10 a, 10 b forming a circuit around the coil in addition to the glass portion 9 which also provides for electrical isolation of the two arms, the arms being conductively joined at the strut end.

Turning now to FIGS. 3-5, there will now be explaining the operation of the ink ejection mechanism 1 for the ejection of ink. Initially, before the paddle 8 has started moving, the situation is as illustrated in FIG. 3 with the nozzle chamber 2 being filled with ink and having a slight bulging meniscus 12. Upon actuation of the actuator mechanism, the paddle 8 begins to move towards the nozzle rim 3 resulting in a substantial increase in pressure in the area around the nozzle rim 3. This in turn results in the situation as illustrated in FIG. 4 wherein the meniscus begins to significantly bulge as a result of the increases in pressure. Subsequently, the actuator is deactivated resulting in a general urge for the paddle 8 to return to its rest position. This results in the ink being sucked back into the chamber 2 which in turn results in the meniscus necking and breaking off into a meniscus 12 and ink drop 14, the drop 14 proceeding to a paper or film medium (not shown) for marking. The meniscus 12 has generally a concave shape and surface tension characteristics result in chamber refilling by means of in flow 13 from an ink supply channel etched through the wafer. The refilling is as a consequence of surface tension forces on the meniscus 12. Eventually the meniscus returns to its quiescent state as illustrated in FIG. 3.

Turning now to FIG. 6, there is illustrated an exploded perspective view of a single ink ejection mechanism 1 illustrating the various material layers. The ink ejection mechanism 1 can be formed as part of a large array of mechanisms forming a print head with multiple print heads being simultaneously formed on a silicon wafer 17. The wafer 17 is initially processed so as to incorporate a standard CMOS circuitry layer 18 which provides for the electrical interconnect for the control of the conductive portions of the actuator. The CMOS layer 18 can be completed with a silicon nitride passivation layer so as to protect it from subsequent processing steps in addition to ink flows through channel 20. The subsequent layers eg. 9, 10 and 2 can be deposited utilizing standard micro-electro mechanical systems (MEMS) construction techniques including the deposit of sacrificial aluminum layers in addition to the deposit of the layers 10 constructed from titanium diboride the layer 9 constructed from glass material and the nozzle chamber proper 2 again constructed from titanium diboride. Each of these layers can be built up in a sacrificial material such as aluminum which is subsequently etched away. Further, an ink supply channel eg. 21 can be etched through the wafer 17. The etching can be by means of an isotropic crystallographic silicon etch or an isotropic dry etch. A dry etch system capable of high aspect ratio silicon trench etching such as the Surface Technology Systems (STS) Advance Silicon Etch (ASE) system is recommended.

Subsequent to construction of the nozzle arrangement 1, it can be attached to an ink supply apparatus for supplying ink to the reverse surface of the wafer 17 so that ink can flow into chamber 2.

The external surface of nozzle chamber 2 including rim 3, in addition to the area surrounding slot 7, can then be hydrophobically treated so as to reduce the possibility of any ink exiting slot 7.

One form of detailed manufacturing process which can be used to fabricate monolithic ink jet print heads operating in accordance with the principles taught by the present embodiment can proceed utilizing the following steps:

1. Using a double sided polished wafer 17, complete drive transistors, data distribution, and timing circuits using a 0.5 micron, one poly, 2 metal CMOS process to form layer 18. This step is shown in FIG. 8. For clarity, these diagrams may not be to scale, and may not represent a cross section though any single plane of the nozzle. FIG. 7 is a key to representations of various materials in these manufacturing diagrams, and those of other cross referenced ink jet configurations.

2. Etch oxide layer 18 down to silicon or aluminum using Mask 1. This mask defines the ink inlet, the heater contact vias, and the edges of the print heads chip. This step is shown in FIG. 9.

3. Deposit 1 micron of sacrificial material 30 (e.g. aluminum)

4. Etch the sacrificial layer 30 using Mask 2, defining the nozzle chamber wall and the actuator anchor point. This step is shown in FIG. 10.

5. Deposit 1 micron of glass 31.

6. Etch the glass using Mask 3, which defines the lower layer of the actuator loop.

7. Deposit 1 micron of heater material 32, for example titanium nitride (TiB₂) or titanium diboride (TiB2). Planarize using CMP. Steps 5 to 7 form a ‘damascene’ process. This step is shown in FIG. 11.

8. Deposit 0.1 micron of silicon nitride (not shown).

9. Deposit 1 micron of glass 33.

10. Etch the glass 33 using Mask 4, which defines the upper layer of the actuator loop.

11. Etch the silicon nitride using Mask 5, which defines the vias connecting the upper layer of the actuator loop to the lower layer of the actuator loop.

12. Deposit 1 micron of the same heater material 34 as in step 7 heater material 32. Planarize using CMP. Steps 8 to 12 form a ‘dual damascene’ process. This step is shown in FIG. 12.

13. Etch the glass down to the sacrificial layer 30 using Mask 6, which defines the actuator and the nozzle chamber wall, with the exception of the nozzle chamber actuator slot. This step is shown in FIG. 13.

14. Wafer probe. All electrical connections are complete at this point, bond pads are accessible, and the chips are not yet separated.

15. Deposit 3 microns of sacrificial material 35.

16. Etch the sacrificial layer 35 down to glass using Mask 7, which defines the nozzle chamber wall, with the exception of the nozzle chamber actuator slot. This step is shown in FIG. 14.

17. Deposit 1 micron of PECVD glass 36 and planarize down to the sacrificial layer 35 using CMP. This step is shown in FIG. 15.

18. Deposit 5 microns of sacrificial material 37.

19. Etch the sacrificial material 37 down to glass using Mask 8. This mask defines the nozzle chamber wall and the paddle. This step is shown in FIG. 16.

20. Deposit 3 microns of PECVD glass 38 and planarize down to the sacrificial layer 37 using CMP.

21. Deposit 1 micron of sacrificial material 39.

22. Etch the sacrificial material 39 down to glass using Mask 9. This mask defines the nozzle chamber wall. This step is shown in FIG. 17.

23. Deposit 3 microns of PECVD glass 40.

24. Etch to a depth of (approx.) 1 micron using Mask 10. This mask defines the nozzle rim 3. This step is shown in FIG. 18.

25. Etch down to the sacrificial layer 39 using Mask 11. This mask defines the roof of the nozzle chamber, and the nozzle itself. This step is shown in FIG. 19.

26. Back-etch completely through the silicon wafer (with, for example, an ASE Advanced Silicon Etcher from Surface Technology Systems) using Mask 12. This mask defines the ink inlets 21 which are etched through the wafer. The wafer is also diced by this etch. This step is shown in FIG. 20.

27. Etch the sacrificial material 30, 35, 37, 39. The nozzle chambers are cleared, the actuators freed, and the chips are separated by this etch. This step is shown in FIG. 21.

28. Mount the print heads in their packaging, which may be a molded plastic former incorporating ink channels which supply the appropriate color ink to the ink inlets at the back of the wafer.

29. Connect the print heads to their interconnect systems. For a low profile connection with minimum disruption of airflow, TAB may be used. Wire bonding may also be used if the printer is to be operated with sufficient clearance to the paper.

30. Hydrophobize the front surface of the print heads.

31. Fill the completed print heads with ink 41 and test them. A filled nozzle is shown in FIG. 22.

The presently disclosed ink jet printing technology is potentially suited to a wide range of printing system including: color and monochrome office printers, short run digital printers, high speed digital printers, offset press supplemental printers, low cost scanning printers high speed pagewidth printers, notebook computers with in-built pagewidth printers, portable color and monochrome printers, color and monochrome copiers, colour and monochrome facsimile machines, combined printer, facsimile and copying machines, label printers, large format plotters, photograph copiers, printers for digital photographic “minilabs”, video printers, PHOTO CD (PHOTO CD is a registered trade mark of the Eastman Kodak Company) printers, portable printers for PDAs, wallpaper printers, indoor sign printers, billboard printers, fabric printers, camera printers and fault tolerant commercial printer arrays.

It would be appreciated by a person skilled in the art that numerous variations and/or modifications may be made to the present invention as shown in the specific embodiments without departing from the spirit or scope of the invention as broadly described. The present embodiments are, therefore, to be considered in all respects to be illustrative and not restrictive.

Ink Jet Technologies

The embodiments of the invention use an ink jet printer type device. Of course many different devices could be used. However presently popular ink jet printing technologies are unlikely to be suitable.

The most significant problem with thermal inkjet is power consumption. This is approximately 100 times that required for high speed, and stems from the energy-inefficient means of drop ejection. This involves the rapid boiling of water to produce a vapor bubble which expels the ink. Water has a very high heat capacity, and must be superheated in thermal ink jet applications. This leads to an efficiency of around 0.02%, from electricity input to drop momentum (and increased surface area) out.

The most significant problem with piezoelectric inkjet is size and cost. Piezoelectric crystals have a very small deflection at reasonable drive voltages, and therefore require a large area for each nozzle. Also, each piezoelectric actuator must be connected to its drive circuit on a separate substrate. This is not a significant problem at the current limit of around 300 nozzles per print head, but is a major impediment to the fabrication of pagewidth print heads with 19,200 nozzles.

Ideally, the inkjet technologies used meet the stringent requirements of in-camera digital color printing and other high quality, high speed, low cost printing applications. To meet the requirements of digital photography, new inkjet technologies have been created. The target features include:

low power (less than 10 Watts)

high resolution capability (1,600 dpi or more)

photographic quality output

low manufacturing cost

small size (pagewidth times minimum cross section)

high speed (<2 seconds per page).

All of these features can be met or exceeded by the inkjet systems described below with differing levels of difficulty. Forty-five different inkjet technologies have been developed by the Assignee to give a wide range of choices for high volume manufacture. These technologies form part of separate applications assigned to the present Assignee as set out in the table below under the heading Cross References to Related Applications.

The inkjet designs shown here are suitable for a wide range of digital printing systems, from battery powered one-time use digital cameras, through to desktop and network printers, and through to commercial printing systems.

For ease of manufacture using standard process equipment, the print head is designed to be a monolithic 0.5 micron CMOS chip with MEMS post processing. For color photographic applications, the print head is 100 mm long, with a width which depends upon the inkjet type. The smallest print head designed is IJ38, which is 0.35 mm wide, giving a chip area of 35 square mm. The print heads each contain 19,200 nozzles plus data and control circuitry.

Ink is supplied to the back of the print head by injection molded plastic ink channels. The molding requires 50 micron features, which can be created using a lithographically micromachined insert in a standard injection molding tool. Ink flows through holes etched through the wafer to the nozzle chambers fabricated on the front surface of the wafer. The print head is connected to the camera circuitry by tape automated bonding.

Cross-Referenced Applications

The following table is a guide to cross-referenced patent applications filed concurrently herewith and discussed hereinafter with the reference being utilized in subsequent tables when referring to a particular case:

Docket No. Reference Title IJ01US IJ01 Radiant Plunger Ink Jet Printer IJ02US IJ02 Electrostatic Ink Jet Printer IJ03US IJ03 Planar Thermoelastic Bend Actuator Ink Jet IJ04US IJ04 Stacked Electrostatic Ink Jet Printer IJ05US IJ05 Reverse Spring Lever Ink Jet Printer IJ06US IJ06 Paddle Type Ink Jet Printer IJ07US IJ07 Permanent Magnet Electromagnetic Ink Jet Printer IJ08US IJ08 Planar Swing Grill Electromagnetic Ink Jet Printer IJ09US IJ09 Pump Action Refill Ink Jet Printer IJ10US IJ10 Pulsed Magnetic Field Ink Jet Printer IJ11US IJ11 Two Plate Reverse Firing Electromagnetic Ink Jet Printer IJ12US IJ12 Linear Stepper Actuator Ink Jet Printer IJ13US IJ13 Gear Driven Shutter Ink Jet Printer IJ14US IJ14 Tapered Magnetic Pole Electromagnetic Ink Jet Printer IJ15US IJ15 Linear Spring Electromagnetic Grill Ink Jet Printer IJ16US IJ16 Lorenz Diaphragm Electromagnetic Ink Jet Printer IJ17US IJ17 PTFE Surface Shooting Shuttered Oscillating Pres- sure Ink Jet Printer IJ18US IJ18 Buckle Grip Oscillating Pressure Ink Jet Printer IJ19US IJ19 Shutter Based Ink Jet Printer IJ20US IJ20 Curling Calyx Thermoelastic Ink Jet Printer IJ21US IJ21 Thermal Actuated Ink Jet Printer IJ22US IJ22 Iris Motion Ink Jet Printer IJ23US IJ23 Direct Firing Thermal Bend Actuator Ink Jet Printer IJ24US IJ24 Conductive PTFE Ben Activator Vented Ink Jet Printer IJ25US IJ25 Magnetostrictive Ink Jet Printer IJ26US IJ26 Shape Memory Alloy Ink Jet Printer IJ27US IJ27 Buckle Plate Ink Jet Printer IJ28US IJ28 Thermal Elastic Rotary Impeller Ink Jet Printer IJ29US IJ29 Thermoelastic Bend Actuator Ink Jet Printer IJ30US IJ30 Thermoelastic Bend Actuator Using PTFE and Corrugated Copper Ink Jet Printer IJ31US IJ31 Bend Actuator Direct Ink Supply Ink Jet Printer IJ32US IJ32 A High Young's Modulus Thermoelastic Ink Jet Printer IJ33US IJ33 Thermally actuated slotted chamber wall ink jet printer IJ34US IJ34 Ink Jet Printer having a thermal actuator comprising an external coiled spring IJ35US IJ35 Trough Container Ink Jet Printer IJ36US IJ36 Dual Chamber Single Vertical Actuator Ink Jet IJ37US IJ37 Dual Nozzle Single Horizontal Fulcrum Actuator Ink Jet IJ38US IJ38 Dual Nozzle Single Horizontal Actuator Ink Jet IJ39US IJ39 A single bend actuator cupped paddle ink jet print- ing device IJ40US IJ40 A thermally actuated ink jet printer having a series of thermal actuator units IJ41US IJ41 A thermally actuated ink jet printer including a tapered heater element IJ42US IJ42 Radial Back-Curling Thermoelastic Ink Jet IJ43US IJ43 Inverted Radial Back-Curling Thermoelastic Ink Jet IJ44US IJ44 Surface bend actuator vented ink supply ink jet printer IJ45US IJ45 Coil Acutuated Magnetic Plate Ink Jet Printer

Tables of Drop-on-Demand Inkjets

Eleven important characteristics of the fundamental operation of individual inkjet nozzles have been identified. These characteristics are largely orthogonal, and so can be elucidated as an eleven dimensional matrix. Most of the eleven axes of this matrix include entries developed by the present assignee.

The following tables form the axes of an eleven dimensional table of inkjet types.

Actuator mechanism (18 types)

Basic operation mode (7 types)

Auxiliary mechanism (8 types)

Actuator amplification or modification method (17 types)

Actuator motion (19 types)

Nozzle refill method (4 types)

Method of restricting back-flow through inlet (10 types)

Nozzle clearing method (9 types)

Nozzle plate construction (9 types)

Drop ejection direction (5 types)

Ink type (7 types)

The complete eleven dimensional table represented by these axes contains 36.9 billion possible configurations of inkjet nozzle. While not all of the possible combinations result in a viable inkjet technology, many million configurations are viable. It is clearly impractical to elucidate all of the possible configurations. Instead, certain inkjet types have been investigated in detail. These are designated IJ01 to IJ45 which matches the docket numbers in the tables under the heading Cross References to Related Applications.

Other inkjet configurations can readily be derived from these forty-five examples by substituting alternative configurations along one or more of the 11 axes. Most of the IJ01 to IJ45 examples can be made into inkjet print heads with characteristics superior to any currently available inkjet technology.

Where there are prior art examples known to the inventor, one or more of these examples are listed in the examples column of the tables below. The IJ01 to IJ45 series are also listed in the examples column. In some cases, a print technology may be listed more than once in a table, where it shares characteristics with more than one entry.

Suitable applications for the ink jet technologies include: Home printers, Office network printers, Short run digital printers, Commercial print systems, Fabric printers, Pocket printers, Internet WWW printers, Video printers, Medical imaging, Wide format printers, Notebook PC printers, Fax machines, Industrial printing systems, Photocopiers, Photographic minilabs etc.

The information associated with the aforementioned 11 dimensional matrix are set out in the following tables.

ACTUATOR MECHANISM (APPLIED ONLY TO SELECTED INK DROPS) Actuator Mech- anism Description Advantages Disadvantages Examples Thermal An electrothermal heater heats the ♦Large force generated ♦High power ♦Canon Bubblejet bubble ink to above boiling point, ♦Simple construction ♦Ink carrier limited to water 1979 Endo et al GB transferring significant heat to the ♦No moving parts ♦Low efficiency patent 2,007,162 aqueous ink. A bubble nucleates and ♦Fast operation ♦High temperatures required ♦Xerox quickly forms, expelling the ink. ♦Small chip area required for ♦High mechanical stress heater-in-pit The efficiency of the process is low, actuator ♦Unusual materials required 1990 Hawkins et al with typically less than 0.05% of the ♦Large drive transistors USP 4,899,181 electrical energy being transformed ♦Cavitation causes actuator failure ♦Hewlett-Packard into kinetic energy of the drop. ♦Kogation reduces bubble formation TIJ ♦Large print heads are difficult to 1982 Vaught et al fabricate USP 4,490,728 Piezo- A piezoelectric crystal such as lead ♦Low power consumption ♦Very large area required for actuator ♦Kyser et al USP electric lanthanum zirconate (PZT) is ♦Many ink types can be used ♦Difficult to integrate with electronics 3,946,398 electrically activated, and either ♦Fast operation ♦High voltage drive transistors required ♦Zoltan USP expands, shears, or bends to apply ♦High efficiency ♦Full pagewidth print heads impractical 3,683,212 pressure to the ink, ejecting drops. due to actuator size ♦1973 Stemme ♦Requires electrical poling in high field USP 3,747,120 strengths during manufacture ♦Epson Stylus ♦Tektronix ♦IJ04 Electro- An electric field is used to activate ♦Low power consumption ♦Low maximum strain (approx. 0.01%) ♦Seiko Epson, Usui strictive electrostriction in relaxor materials ♦Many ink types can be used ♦Large area required for actuator due et all JP 253401196 such as lead tanthanum zirconate ♦Low thermal expansion low strain ♦IJ04 titanate (PLZT) or lead magnesium ♦Electric field strength ♦Response speed is marginal (˜10 μs) niobate (PMN). required (approx. 3.5 V/μm) ♦High voltage drive transistors required can be generated without ♦Full pagewidth print heads impractical difficulty due to actuator size ♦Does not require electrical poling Ferro- An electric field is used to induce a ♦Low power consumption ♦Difficult to integrate with electronics ♦IJ04 electric phase transition between the ♦Many ink types can be used ♦Unusual materials such as antiferroelectric (AFE) and ♦Fast operation (<1 μs) PLZSnT are required ferroelectric (FE) phase. Perovskite ♦Relatively high longitudinal ♦Actuators require a large area materials such as tin modified lead strain tanthanum zirconate titanate ♦High efficiency (PLZSnT) exhibit large strains of up ♦Electric field strength of to 1% associated with the AFE to FE around 3 V/μm can be phase transition. readily provided Electro- Conductive plates are separated by a ♦Low power consumption ♦Difficult to operate electrostatic ♦IJ02, IJ04 static compressible or fluid dielectric ♦Many ink types can be used devices in an aqueous environment plates (usually air). Upon application of a ♦Fast operation ♦The electrostatic actuator will nor- voltage, the plates attract each other mally need to be separated from the ink and displace ink, causing drop ♦Very large area required to achieve ejection. The conductive plates may high forces be in a comb or honeycomb ♦High voltage drive transistors may be structure, or stacked to increase the required surface area and therefore the force. ♦Full pagewidth print heads are not competitive due to actuator size Electro- A strong electric field is applied to ♦Low current consumption ♦High voltage required ♦1989 Saito et al, static the ink, whereupon electrostatic ♦Low temperature ♦May be damaged by sparks due to air USP 4,799,068 pull on attraction accelerates the ink towards breakdown ♦1989 Miura et al, ink the print medium. ♦Required field strength increases USP 4,810,954 as the drop size decreases ♦Tone-jet ♦High voltage drive transistors required ♦Electrostatic field attracts dust Permanent An electromagnet directly attracts a ♦Low power consumption ♦Complex fabrication ♦IJ07, IJ10 magnet permanent magnet, displacing ink ♦Many ink types can be used ♦Permanent magnetic material such as electro- and causing drop ejection. Rare earth ♦Fast operation Neodymium Iron Boron (NdFeB) magnetic magnets with a field strength around ♦High efficiency required. 1 Tesla can be used. Examples are: ♦Easy extension from single ♦High local currents required Samarium Cobalt (SaCo) and nozzles to pagewidth print ♦Copper metalization should be used magnetic materials in the heads for long electromigration lifetime neodymium iron boron family and low resistivity (NdFeB, NdDyFeBNb, NdDyFeB, ♦Pigmented inks are usually infeasible etc) ♦Operating temperature limited to the Curie temperature (around 540K) Soft A solenoid induced a magnetic field ♦Low power consumption ♦Complex fabrication ♦IJ01, IJ05, IJ08, magnetic in a soft magnetic core or yoke ♦Many ink types can be used ♦Materials not usually present in a ♦IJ10 IJ12, IJ14, core fabricated from a ferrous material ♦Fast operation CMOS fab such as NiFe, CoNiFe, or ♦IJ15, IJ17 electro- such as electroplated iron alloys such ♦High efficiency CoFe are required magnetic as CoNiFe [1], CoFe, or NiFe alloys. ♦Easy extension from single ♦High local currents required Typically, the soft magnetic material nozzles to pagewidth print ♦Copper metalization should be used is in two parts, which are normally heads for long electromigration lifetime held apart by a spring. When the and low resistivity solenoid is actuated, the two parts ♦Electroplating is required attract, displacing the ink. ♦High saturation flux density is requir- ed (2.0-2.1 T is achievable with CoNiFe [1]) Magnetic The Lorenz force acting on a current ♦Low power consumption ♦Force acts as a twisting motion ♦IJ06, IJ11, IJ13, Lorenz carrying wire in a magnetic field is ♦Many ink types can be used ♦Typically, only a quarter of the IJ16 force utilized. ♦Fast operation solenoid length provides force in a This allows the magnetic field to be ♦High efficiency useful direction supplied externally to the print head, ♦Easy extension from single ♦High local currents required for example with rare earth nozzles to pagewidth print ♦Copper metalization should be used permanent magnets. heads for long electromigration lifetime Only the current carrying wire need and low resistivity be fabricated on the print-head, ♦Pigmented inks are usually infeasible simplifying materials requirements. Magneto- The actuator uses the giant ♦Many ink types can be used ♦Force acts as a twisting motion ♦Fischenbeck, USP striction magnetostrictive effect of materials ♦Fast operation ♦Unusual materials such as Terfenol-D 4,032,929 such as Terfenol-D (an alloy of ♦Easy extension from single are required ♦IJ25 terbium, dysprosium and iron nozzles to pagewidth print ♦High local currents required developed at the Naval Ordnance heads ♦Copper metalization should be used Laboratory, hence Ter-Fe-NOL). For ♦High force is available for long electromigration lifetime best efficiency, the actuator should and low resistivity be pre-stressed to approx. 8 MPa. ♦Pre-stressing may be required Surface Ink under positive pressure is held in ♦Low power consumption ♦Requires supplementary force to ♦Silverbrook, tension a nozzle by surface tension. The ♦Simple construction effect drop separation EP 0771 reduction surface tension of the ink is reduced ♦No unusual materials ♦Requires special ink surfactants 658 A2 and related below the bubble threshold, causing required in fabrication ♦Speed may be limited by surfactant patent applications the ink to egress from the nozzle. ♦High efficiency properties ♦Easy extension from single nozzles to pagewidth print heads Viscosity The ink viscosity is locally reduced ♦Simple construction ♦Requires supplementary force to ♦Silverbrook, reduction to select which drops are to be ♦No unusual materials effect drop separation EP 0771 ejected. A viscosity reduction can be required in fabrication ♦Requires special ink viscosity 658 A2 and related achieved electrothermally with most ♦Easy extension from single properties patent applications inks, but special inks can be nozzles to pagewidth print ♦High speed is difficult to achieve engineered for a 100:1 viscosity heads ♦Requires oscillating ink pressure reduction. ♦A high temperature difference (typically 80 degrees) is required Acoustic An acoustic wave is generated and ♦Can operate without a ♦Complex drive circuitry ♦1993 Hadimioglu focused upon the drop ejection nozzle plate ♦Complex fabrication et al, EUP 550,192 region. ♦Low efficiency ♦1993 Elrod et al, ♦Poor control of drop position EUP 572,220 ♦Poor control of drop volume Thermo- An actuator which relies upon ♦Low power consumption ♦Efficient aqueous operation requires a ♦IJ03, IJ09, IJ17, elastic differential thermal expansion upon ♦Many ink types can be used thermal insulator on the hot side ♦IJ18 IJ19, IJ20, bend Joule heating is used. ♦Simple planar fabrication ♦Corrosion prevention can be difficult ♦IJ21, IJ22 IJ23, actuator ♦Small chip area required for ♦Pigmented inks may be infeasible, as ♦IJ24, IJ27, IJ28 each actuator pigment particles may jam the bend ♦IJ29, IJ30, IJ31, ♦Fast operation actuator ♦IJ32 IJ33, IJ34, ♦High efficiency ♦IJ35, IJ36 IJ37, ♦CMOS compatible voltages ♦IJ38 ,IJ39, IJ40 and currents ♦IJ41 ♦Standard MEMS processes can be used ♦Easy extension from single nozzles to pagewidth print heads High CTE A material with a very high ♦High force can be generated ♦Requires special material (e.g. PTFE) ♦IJ09, IJ17, IJ18, thermo- coefficient of thermal expansion ♦PTFE is a candidate for low ♦Requires a PTFE deposition process, ♦IJ21 IJ21, IJ22, elastic (CTE) such as dielectric constant which is not yet standard in ULSI fabs ♦IJ23, IJ24 IJ27, actuator polytetrafluoroethylene (PTFE) is insulation in ULSI ♦PTFE deposition cannot be followed ♦IJ28, IJ29, IJ30 used. As high CTE materials are ♦Very low power with high temperature (above 350° C.) ♦IJ31, IJ42, IJ43, usually non-conductive, a heater consumption processing ♦IJ44 fabricated from a conductive ♦Many ink types can be used ♦Pigmented inks may be infeasible, as material is incorporated. A 50 μm ♦Simple planar fabrication pigment particles may jam the bend long PTFE bend actuator with ♦Small chip area required for actuator polysilicon heater and 15 mW power each actuator input can provide 180 μN force and Fast operation 10 μm deflection. Actuator motions ♦High efficiency include: ♦CMOS compatible voltages 1) Bend and currents 2) Push ♦Easy extension from single 3) Buckle nozzles to pagewidth print 4) Rotate heads Conduc- A polymer with a high coefficient of ♦High force can be generated ♦Requires special materials ♦IJ24 tive thermal expansion (such as PTFB) is ♦Very low power development (High CTE conductive polymer doped with conducting substances to consumption polymer) thermo- increase its conductivity to about 3 ♦Many ink types can be used ♦Requires a PTFE deposition process, elastic orders of magnitude below that of ♦Simple planar fabrication which is not yet standard in ULSI fabs actuator copper. The conducting polymer ♦Small chip area required for ♦PTFE deposition cannot be followed expands when resistively heated. each actuator with high temperature (above 350° C.) Examples of conducting dopants ♦Fast operation processing include: ♦High efficiency ♦Evaporation and CVD deposition 1) Carbon nanotubes ♦CMOS compatible voltages techniques cannot be used 2) Metal fibers and currents ♦Pigmented inks may be infeasible, as 3) Conductive polymers such as ♦Easy extension from single pigment particles may jam the bend doped polythiophene nozzles to pagewidth print actuator 4) Carbon granules heads Shape A shape memory alloy such as TiNi ♦High force is available ♦Fatigue limits maximum number of ♦IJ26 memory (also known as Nitinol-Nickel (stresses of hundreds of cycles alloy Titanium alloy developed at the MPa) ♦Low strain (1%) is required to extend Naval Ordnance Laboratory) is ♦Large strain is available fatigue resistance thermally switched between its weak (more than 3%) ♦Cycle rate limited by heat removal martensitic state and its high ♦High corrosion resistance ♦Requires unusual materials (TiNi) stiffness austenic state. The shape of ♦Simple construction ♦The latent heat of transformation must the actuator in its martensitic state is ♦Easy extension from single be provided deformed relative to the austenic nozzles to pagewidth print ♦High current operation shape. The shape change causes heads ♦Requires pre-stressing to distort the ejection of a drop. ♦Low voltage operation martensitic state Linear Linear magnetic actuators include ♦Linear Magnetic actuators ♦Requires unusual semiconductor ♦IJ12 Magnetic the Linear Induction Actuator (LIA), can be constructed with materials such as soft magnetic alloys Actuator Linear Permanent Magnet high thrust, long travel, and (e.g. CoNiFe [1]) Synchronous Actuator (LPMSA), high efficiency using planar ♦Some varieties also require perm- Linear Reluctance Synchronous semiconductor fabrication anent magnetic materials such Actuator (LRSA), Linear Switched techniques as Neodymium iron boron (NdFeB) Reluctance Actuator (LSRA), and ♦Long actuator travel is ♦Requires complex multi-phase drive the Linear Stepper Actuator (LSA). available circuitry ♦Medium force is available ♦High current operation ♦Low voltage operation

BASIC OPERATION MODE. Operational mode Description Advantages Disadvantages Examples Actuator This is the simplest mode of ♦Simple operation ♦Drop repetition rate is usually limited ♦Thermal inkjet directly operation: the actuator directly ♦No external fields required to less than 10 KHz. However, this is ♦Piezoelectric pushes ink supplies sufficient kinetic energy to ♦Satellite drops can be not fundamental to the method, but is inkjet expel the drop. The drop must have a avoided if drop velocity is related to the refill method normally ♦IJ01, IJ02, IJ03, sufficient velocity to overcome the less than 4 m/s used ♦IJ04 IJ05, IJ06, surface tension. ♦Can be efficient, depending ♦All of the drop kinetic energy must be ♦IJ07, IJ09 IJ11, upon the actuator used provided by the actuator ♦IJ12, IJ14, IJ16 ♦Satellite drops usually form if drop ♦IJ20, IJ22, IJ23, velocity is greater than 4.5 m/s ♦IJ24 IJ25, IJ26, ♦IJ27, IJ28 IJ29, ♦IJ30, IJ31, IJ32 ♦IJ33, IJ34, IJ35, ♦IJ36 IJ37, IJ38, ♦IJ39, IJ40 IJ41, ♦IJ42, IJ43, IJ44 Proximity The drops to be printed are selected ♦Very simple print head ♦Requires close proximity between the ♦Silverbrook, by some manner (e.g. thermally fabrication can be used print head and the print media or EP 0771 induced surface tension reduction of ♦The drop selection means transfer roller 658 A2 and related pressurized ink). Selected drops are does not need to provide the ♦May require two print heads printing patent applications separated from the ink in the nozzle energy required to separate alternate rows of the image by contact with the print medium or the drop from the nozzle ♦Monolithic color print heads are a transfer roller. difficult Electrostatic The drops to be printed are selected ♦Very simple print head ♦Requires very high electrostatic field ♦Silverbrook, pull on ink by some manner (e.g. thermally fabrication can be used ♦Electrostatic field for small nozzle EP 0771 induced surface tension reduction of ♦The drop selection means sizes is above air breakdown 658 A2 and related pressurized ink). Selected drops are does not need to provide the ♦Electrostatic field may attract dust patent applications separated from the ink in the nozzle energy required to separate ♦Tone-Jet by a strong electric field. the drop from the nozzle Magnetic The drops to be printed are selected ♦Very simple print head ♦Requires magnetic ink ♦Silverbrook, pull on by some manner (e.g. thermally fabrication can be used ♦Ink colors other than black are EP 0771 ink induced surface tension reduction of ♦The drop selection means difficult 658 A2 and pressurized ink). Selected drops are does not need to provide the ♦Requires very high magnetic related patent separated from the ink in the nozzle energy required to separate fields applications by a strong magnetic field acting on the drop from the nozzle the magnetic ink. Shutter The actuator moves a shutter to ♦High speed (>50 KHz) ♦Moving parts are required ♦IJ13, IJ17, IJ21 block ink flow to the nozzle. The ink operation can be achieved ♦Requires ink pressure modulator pressure is pulsed at a multiple of the due to reduced refill time ♦Friction and wear must be considered drop ejection frequency. ♦Drop timing can be very ♦Stiction is possible accurate ♦The actuator energy can be very low Shuttered The actuator moves a shutter to ♦Actuators with small travel ♦Moving parts are required ♦IJ08, IJ15, IJ18, grill block ink flow through a grill to the can be used ♦Requires ink pressure modulator IJ19 nozzle. The shutter movement need ♦Actuators with small force ♦Friction and wear must be considered only be equal to the width of the grill can be used ♦Stiction is possible holes. ♦High speed (>50 KHz) operation can be achieved Pulsed A pulsed magnetic field attracts an ♦Extremely low energy ♦Requires an external pulsed magnetic ♦IJ10 magnetic ‘ink pusher’ at the drop ejection operation is possible field pull on frequency. An actuator controls a ♦No heat dissipation ♦Requires special materials for both the ink pusher catch, which prevents the ink pusher problems actuator and the ink pusher from moving when a drop is not to ♦Complex construction be ejected.

AUXILIARY MECHANISM (APPLIED TO ALL NOZZLES) Auxiliary Mech- anism Description Advantages Disadvantages Examples None The actuator directly fires the ink ♦Simplicity of construction ♦Drop ejection energy must be supplied ♦Most inkjets, drop, and there is no external field or ♦Simplicity of operation by individual nozzle actuator including other mechanism required. ♦Small physical size piezoelectric and thermal bubble. ♦IJ01-IJ07, IJ09, ♦IJ11 IJ12, IJ14, ♦IJ20, IJ22 ♦IJ23-IJ45 Oscillating The ink pressure oscillates, ♦Oscillating ink pressure can ♦Requires external ink pressure ♦Silverbrook, ink providing much of the drop ejection provide a refill pulse, oscillator EP 0771 pressure energy. The actuator selects which allowing higher operating ♦Ink pressure phase and amplitude 658 A2 and related (including drops are to be fired by selectively speed must be carefully controlled patent applications acoustic blocking or enabling nozzles. The ♦The actuators may operate ♦Acoustic reflections in the ♦IJ08, IJ13, IJ15, stimula- ink pressure oscillation may be with much lower energy ink chamber must be designed for ♦IJ17 tion) achieved by vibrating the print head, ♦Acoustic lenses can be used ♦IJ18, IJ19, IJ21 or preferably by an actuator in the to focus the sound on the ink supply. nozzles Media The print head is placed in close ♦Low power ♦Precision assembly required ♦Silverbrook, proximity proximity to the print medium. ♦High accuracy ♦Paper fibers may cause problems EP 0771 Selected drops protrude from the ♦Simple print head ♦Cannot print on rough substrates 658 A2 and related print head further than unselected construction patent applications drops, and contact the print medium. The drop soaks into the medium fast enough to cause drop separation. Transfer Drops are printed to a transfer roller ♦High accuracy ♦Bulky ♦Silverbrook, roller instead of straight to the print ♦Wide range of print ♦Expensive EP 0771 medium. A transfer roller can also be substrates can be used ♦Complex construction 658 A2 and related used for proximity drop separation. ♦Ink can be dried on the patent applications transfer roller ♦Tektronix hot melt piezoelectric inkjet ♦Any of the IJ series Electro- An electric field is used to accelerate ♦Low power ♦Field strength required for separation ♦Silverbrook, static selected drops towards the print ♦Simple print head of small drops is near or above air EP 0771 medium. construction breakdown 658 A2 and related patent applications ♦Tone-Jet Direct A magnetic field is used to accelerate ♦Low power ♦Requires magnetic ink ♦Silverbrook, magnetic selected drops of magnetic ink ♦Simple print head ♦Requires strong magnetic field EP 0771 field towards the print medium. construction 658 A2 and related patent applications Cross The print head is placed in a constant ♦Does not require magnetic ♦Requires external magnet ♦IJ06, IJ16 magnetic magnetic field. The Lorenz force in a materials to be integrated in ♦Current densities may be high, field current carrying wire is used to move the print head resulting in electromigration problems the actuator. manufacturing process Pulsed A pulsed magnetic field is used to ♦Very low power operation ♦Complex print head construction ♦IJ10 magnetic cyclically attract a paddle, which is possible ♦Magnetic materials required in print field pushes on the ink. A small actuator ♦Small print head size head moves a catch, which selectively prevents the paddle from moving.

ACTUATOR AMPLIFICATION OR MODIFICATION METHOD Actuator ampli- fication Description Advantages Disadvantages Examples None No actuator mechanical ♦Operational simplicity ♦Many actuator mechanisms have ♦Thermal Bubble amplification is used. The actuator insufficient travel, or insufficient force, Inkjet directly drives the drop ejection to efficiently drive the drop ejection ♦IJ01, IJ02, IJ06, IJ07 process. process ♦IJ16, IJ25, IJ26 Differen- An actuator material expands more ♦Provides greater travel in a ♦High stresses are involved ♦Piezoelectric tial on one side than on the other. The reduced print head area ♦Care must be taken that the materials ♦IJ03, IJ09, expansion expansion may be thermal, ♦The bend actuator converts do not delaminate ♦IJ17-IJ24 bend piezoelectric, magnetostrictive, or a high force low travel ♦Residual bend resulting from high ♦IJ27, IJ29-IJ39, actuator other mechanism. actuator mechanism to high temperature or high stress during ♦IJ42, IJ43, IJ44 travel, lower force formation mechanism. Transient A trilayer bend actuator where the ♦Very good temperature ♦High stresses are involved ♦IJ40, IJ41 bend two outside layers are identical. This stability ♦Care must be taken that the actuator cancels bend due to ambient ♦High speed, as a new drop materials do not delaminate temperature and residual stress. The can be fired before heat actuator only responds to transient dissipates heating of one side or the other. ♦Cancels residual stress of formation Actuator A series of thin actuators are stacked. ♦Increased travel ♦Increased fabrication complexity ♦Some piezoelectric stack This can be appropriate where ♦Reduced drive voltage ♦Increased possibility of short circuits ink jets actuators require high electric field due to pinholes ♦IJ04 strength, such as electrostatic and piezoelectric actuators. Multiple Multiple smaller actuators are used ♦Increases the force available ♦Actuator forces may not add linearly, ♦IJ12, IJ13, IJ18, IJ20 actuators simultaneously to move the ink. from an actuator reducing efficiency ♦IJ22, IJ28, IJ42, IJ43 Bach actuator need provide only a ♦Multiple actuators can be portion of the force required. positioned to control ink flow accurately Linear A linear spring is used to transform a ♦Matches low travel actuator ♦Requires print head area for the spring ♦IJ15 Spring motion with small travel and high with higher travel force into a longer travel, lower force requirements motion. ♦Non-contact method of motion transformation Reverse The actuator loads a spring. When ♦Better coupling to the ink ♦Fabrication complexity ♦IJ05, IJ11 spring the actuator is turned off, the spring ♦High stress in the spring releases. This can reverse the force/distance curve of the actuator to make it compatible with the force/time requirements of the drop ejection. Coiled A bend actuator is coiled to provide ♦Increases travel ♦Generally restricted to planar ♦IJ17, IJ21, IJ34, IJ35 actuator greater travel in a reduced chip area. ♦Reduces chip area implementations due to extreme ♦Planar implementations are fabrication difficulty in other relatively easy to fabricate. orientations. Flexure A bend actuator has a small region ♦Simple, means of increasing ♦Care must be taken not to exceed the ♦IJ10, IJ19, IJ33 bend near the fixture point, which flexes travel of a bend actuator elastic limit in the flexure area actuator much more readily than the ♦Stress distribution is very uneven remainder of the actuator. The ♦Difficult to accurately model with actuator flexing is effectively finite element analysis converted from an even coiling to an angular bend, resulting in greater travel of the actuator tip. Gears Gears can be used to increase travel ♦Low force, tow travel ♦Moving parts are required ♦IJ13 at the expense of duration. Circular actuators can be used ♦Several actuator cycles are required gears, rack and pinion, ratchets, and ♦Can be fabricated using ♦More complex drive electronics other gearing methods can be used. standard surface MEMS ♦Complex construction processes ♦Friction, friction, and wear are possible Catch The actuator controls a small catch. ♦Very low actuator energy ♦Complex construction ♦IJ10 The catch either enables or disables ♦Very small actuator size ♦Requires external force movement of an ink pusher that is ♦Unsuitable for pigmented inks controlled in a bulk manner. Buckle A buckle plate can be used to change ♦Very fast movement ♦Must stay within elastic limits of the ♦S. Hirata et al, plate a slow actuator into a fast motion. It achievable materials for long device life “An Ink-jet can also convert a high force, low ♦High stresses involved Head. . .”, travel actuator into a high travel, ♦Generally high power Proc. IEEE MEMS, medium force motion. requirement Feb. 1996, pp418-423. ♦IJ18,IJ27 Tapered A tapered magnetic pole can increase ♦Linearizes the magnetic ♦Complex construction ♦IJ14 magnetic travel at the expense of force. force/distance curve pole Lever A lever and fulcrum is used to ♦Matches low travel actuator ♦High stress around the fulcrum ♦IJ32, IJ36, IJ37 transform a motion with small travel with higher travel and high force into a motion with requirements longer travel and lower force. The ♦Fulcrum area has no linear lever can also reverse the direction of movement, and can be used travel. for a fluid seal Rotary The actuator is connected to a rotary ♦High mechanical advantage ♦Complex construction ♦IJ28 impeller impeller. A small angular deflection ♦The ratio of force to travel ♦Unsuitable for pigmented inks of the actuator results in a rotation of of the actuator can be the impeller vanes, which push the matched to the nozzle ink against stationary vanes and out requirements by varying the of the nozzle. number of impeller vanes Acoustic A refractive or diffractive (e.g. zone ♦No moving parts ♦Large area required ♦1993 Hadimioglu et lens plate) acoustic lens is used to ♦Only relevant for acoustic al, EUP 550,192 concentrate sound waves. ink jets ♦1993 Elrod et al, EUP 572,220 Sharp A sharp point is used to concentrate ♦Simple construction ♦Difficult to fabricate using standard ♦Tone-jet conductive an electrostatic field. VLSI processes for a surface ejecting point ink-jet ♦Only relevant for electrostatic ink jets

ACTUATOR MOTION Actuator motion Description Advantages Disadvantages Examples Volume The volume of the actuator changes, ♦Simple construction in the ♦High energy is typically required to ♦Hewlett-Packard expansion pushing the ink in all directions. case of thermal ink jet achieve volume expansion. This leads Thermal Inkjet to thermal stress, cavitation, and ♦Canon Bubblejet kogation in thermal ink jet implementations Linear, The actuator moves in a direction ♦Efficient coupling to ink ♦High fabrication complexity may be ♦IJ01, IJ02, IJ04, IJ07 normal normal to the print head surface. The drops ejected normal to the required to achieve perpendicular ♦IJ11, IJ14 to chip nozzle is typically in the line of surface motion surface movement. Linear, The actuator moves parallel to the ♦Suitable for planar ♦Fabrication complexity ♦IJ12, IJ13, IJ15, parallel print head surface. Drop ejection fabrication ♦Friction ♦IJ33, IJ34, IJ35, IJ36 to chip may still be normal to the surface. ♦Stiction surface Membrane An actuator with a high force but ♦The effective area of the ♦Fabrication complexity ♦1982 Hawkins USP push small area is used to push a stiff actuator becomes the ♦Actuator size 4,459,601 membrane that is in contact with the membrane area ♦Difficulty of integration in a VLSI ink. process Rotary The actuator causes the rotation of ♦Rotary levers may be used ♦Device complexity ♦IJ05, IJ08, IJ13, IJ28 some element, such a grill or to increase travel ♦May have friction at a pivot point impeller ♦Small chip area requirements Bend The actuator bends when energized. ♦A very small change in ♦Requires the actuator to be made from ♦1970 Kyser et al This may be due to differential dimensions can be at least two distinct layers, or to have a USP 3,946,398 thermal expansion, piezoelectric converted to a large motion. thermal difference across the actuator ♦1973 Stemme USP expansion, magnetostriction, or other 3,747,120 form of relative dimensional change. ♦IJ03, IJ09, IJ10, IJ19 ♦IJ23, IJ24, IJ25, IJ29 ♦IJ30, IJ31, IJ33, IJ34 ♦IJ35 Swivel The actuator swivels around a central ♦Allows operation where the ♦Inefficient coupling to the ink motion ♦IJ06 pivot. This motion is suitable where net linear force on the there are opposite forces applied to paddle is zero opposite sides of the paddle, e.g. ♦Small chip area Lorenz force. requirements Straighten The actuator is normally bent, and ♦Can be used with shape ♦Requires careful balance of stresses to ♦IJ26, IJ32 straightens when energized. memory alloys where the ensure that the quiescent bend is austenic phase is planar accurate Double The actuator bends in one direction ♦One actuator can be used to ♦Difficult to make the drops ejected by ♦IJ36, IJ37, IJ38 bend when one element is energized, and power two nozzles. both bend directions identical. bends the other way when another ♦Reduced chip size. ♦A small efficiency loss compared to element is energized. ♦Not sensitive to ambient equivalent single bend actuators. temperature Shear Energizing the actuator causes a ♦Can increase the effective ♦Not readily applicable to other actuator ♦1985 Fishbeck USP shear motion in the actuator material. travel of piezoelectric mechanisms 4,584,590 actuators Radial The actuator squeezes an ink ♦Relatively easy to fabricate ♦High force required ♦1970 Zoltan USP constric- reservoir, forcing ink from a single nozzles from glass ♦Inefficient 3,683,212 tion constricted nozzle. tubing as macroscopic ♦Difficult to integrate with VLSI structures processes Coil/ A coiled actuator uncoils or coils ♦Easy to fabricate as a planar ♦Difficult to fabricate for non-planar ♦IJ17, IJ21, IJ34, IJ35 uncoil more tightly. The motion of the free VLSI process devices end of the actuator ejects the ink. ♦Small area required, ♦Poor out-of-plane stiffness therefore low cost Bow The actuator bows (or buckles) in the ♦Can increase the speed of ♦Maximum travel is constrained ♦IJ16, IJ18, IJ27 middle when energized. travel ♦High force required ♦Mechanically rigid Push-Pull Two actuators control a shutter. One ♦The structure is pinned at ♦Not readily suitable for inkjets which ♦IJ18 actuator pulls the shutter, and the both ends, so has a high directly push the ink other pushes it. out-of-plane rigidity Curl A set of actuators curl inwards to ♦Good fluid flow to the ♦Design complexity ♦IJ20, IJ42 inwards reduce the volume of ink that they region behind the actuator enclose. increases efficiency Curl A set of actuators curl outwards, ♦Relatively simple ♦Relatively large chip area ♦IJ43 outwards pressurizing ink in a chamber construction surrounding the actuators, and expelling ink from a nozzle in the chamber. Iris Multiple vanes enclose a volume of ♦High efficiency ♦High fabrication complexity ♦IJ22 ink. These simultaneously rotate, ♦Small chip area ♦Not suitable for pigmented inks reducing the volume between the vanes. Acoustic The actuator vibrates at a high ♦The actuator can be ♦Large area required for efficient ♦1993 Hadimiogtu et vibration frequency. physically distant from the operation at useful frequencies al, EUP 550, 192 ink ♦Acoustic coupling and crosstalk ♦1993 Elrod et al, ♦Complex drive circuitry EUP 572,220 ♦Poor control of drop volume and position None In various ink jet designs the actuator ♦No moving parts ♦Various other tradeoffs are required to ♦Silverbrook, does not move. eliminate moving parts EP 0771 658 A2 and related patent applications ♦Tone-jet

NOZZLE REFILL METHOD Nozzle refill method Description Advantages Disadvantages Examples Surface After the actuator is energized, it ♦Fabrication simplicity ♦Low speed ♦Thermal inkjet tension typically returns rapidly to its normal ♦Operational simplicity ♦Surface tension force relatively small ♦Piezoelectric position. This rapid return sucks in compared to actuator force inkjet air through the nozzle opening. The ♦Long refill time usually dominates the ♦IJ01-IJ07, IJ10-IJ14 ink surface tension at the nozzle then total repetition rate ♦IJ16, IJ20, IJ22-IJ45 exerts a small force restoring the meniscus to a minimum area. Shuttered Ink to the nozzle chamber is ♦High speed ♦Requires common ink pressure ♦IJ08, IJ13, IJ15, IJ17 oscillating provided at a pressure that oscillates ♦Low actuator energy, as the oscillator ♦IJ18, IJ19, IJ21 ink at twice the drop ejection frequency. actuator need only open or ♦May not be suitable for pigmented inks pressure When a drop is to be ejected, the close the shutter, instead of shutter is opened for 3 half cycles: ejecting the ink drop drop ejection, actuator return, and refill. Refill After the main actuator has ejected a ♦High speed, as the nozzle is ♦Requires two independent actuators per ♦IJ09 actuator drop a second (refill) actuator is actively refilled nozzle energized. The refill actuator pushes ink into the nozzle chamber. The refill actuator returns slowly, to prevent its return from emptying the chamber again. Positive The ink is held a slight positive ♦High refill rate, therefore a ♦Surface spill must be prevented ♦Silverbrook, ink pressure. After the ink drop is high drop repetition rate is ♦Highly hydrophobic print head EP 0771 pressure ejected, the nozzle chamber fills possible surfaces are required 658 A2 and related quickly as surface tension and ink patent applications pressure both operate to refill the ♦Alterative for: nozzle. ♦IJ01-IJ07, IJ10-IJ14 ♦IJ16, IJ20, IJ22-IJ45

METHOD OF RESTRICTING BACK-FLOW THROUGH INLET Inlet back-flow restriction method Description Advantages Disadvantages Examples Long inlet The ink inlet channel to the nozzle ♦Design simplicity ♦Restricts refill rate ♦Thermal inkjet channel chamber is made long and relatively ♦Operational simplicity ♦May result in a relatively large chip ♦Piezoelectric inkjet narrow, relying on viscous drag to ♦Reduces crosstalk area ♦IJ42, IJ43 reduce inlet back-flow. ♦Only partially effective Positive The ink is under a positive pressure, ♦Drop selection and ♦Requires a method (such as a nozzle ♦Silverbrook, ink so that in the quiescent state some of separation forces can be rim or effective hydrophobizing, or EP 0771 pressure the ink drop already protrudes from reduced both) to prevent flooding of the 658 A2 and related the nozzle. ♦Fast refill time ejection surface of the print head. patent applications This reduces the pressure in the ♦Possible operation of nozzle chamber which is required to the following: eject a certain volume of ink. The ♦IJ01-IJ07, IJ09-IJ12 reduction in chamber pressure results ♦IJ14, IJ16, IJ20, in a reduction in ink pushed out ♦IJ22, IJ23-IJ34, through the inlet. IJ36-IJ41 IJ44 Baffle One or more baffles are placed in the ♦The refill rate is not as ♦Design complexity ♦HP Thermal Ink Jet inlet ink flow. When the actuator is restricted as the long inlet ♦May increase fabrication complexity ♦Tektronix energized, the rapid ink movement method. (e.g. Tektronix hot melt Piezoelectric piezoelectric ink jet creates eddies which restrict the flow ♦Reduces crosstalk print heads). through the inlet. The slower refill process is unrestricted, and does not result in eddies. Flexible In this method recently disclosed by ♦Significantly reduces back- ♦Not applicable to most inkjet ♦Canon flap Canon, the expanding actuator flow for edge-shooter configurations restricts (bubble) pushes on a flexible flap thermal ink jet devices ♦Increased fabrication complexity inlet that restricts the inlet. ♦Inelastic deformation of polymer flap results in creep over extended use Inlet A filter is located between the ink ♦Additional advantage of ink ♦Restricts refill rate ♦IJ04, IJ12, IJ24, IJ27 filter inlet and the nozzle chamber. The filtration ♦May result in complex construction ♦IJ29, IJ30 filter has a multitude of small holes ♦Ink filter may be fabricated or slots, restricting ink flow. The with no additional process filter also removes particles which steps may block the nozzle. Small The ink inlet channel to the nozzle ♦Design simplicity ♦Restricts refill rate ♦IJ02, IJ37, IJ44 inlet chamber has a substantially smaller ♦May result in a relatively large compared cross section than that of the nozzle, chip area to nozzle resulting in easier ink egress out of ♦Only partially effective the nozzle than out of the inlet. Inlet A secondary actuator controls the ♦Increases speed of the ink- ♦Requires separate refill actuator ♦IJ09 shutter position of a shutter, closing off the jet print head operation and drive circuit ink inlet when the main actuator is energized. The inlet The method avoids the problem of ♦Back-flow problem is ♦Requires careful design to minimize ♦IJ01, IJ03, IJ05, IJ06 is located inlet back-flow by arranging the ink- eliminated the negative pressure behind the paddle ♦IJ07, IJ10, IJ11, IJ14 behind pushing surface of the actuator ♦IJ16, IJ22, IJ23, IJ25 the ink- between the inlet and the nozzle. ♦IJ28, IJ31, IJ32, IJ33 pushing ♦IJ34, IJ35, IJ36, IJ39 surface ♦IJ40, IJ41 Part of The actuator and a wall of the ink ♦Significant reductions in ♦Small increase in fabrication ♦IJ07, IJ20, IJ26, IJ38 the chamber are arranged so that the back-flow can be achieved complexity actuator motion of the actuator closes off the ♦Compact designs possible moves to inlet. shut off the inlet Nozzle In some configurations of ink jet, ♦Ink back-flow problem is ♦None related to ink back-flow on ♦Silverbrook, actuator there is no expansion or movement eliminated actuation EP 0771 does not of an actuator which may cause ink 658 A2 and related result in back-flow through the inlet. patent applications ink ♦Valve-jet back-flow ♦Tone-jet ♦IJ08, IJ13, IJ15, IJ17 ♦IJ18, IJ19, IJ21

NOZZLE CLEARING METHOD Nozzle Clearing method Description Advantages Disadvantages Examples Normal All of the nozzles are fired ♦No added complexity on the ♦May not be sufficient to displace dried ♦Most ink jet systems nozzle periodically, before the ink has a print head ink ♦IJ01-IJ07, IJ09-IJ12 firing chance to dry. When not in use the ♦IJ14, IJ16, IJ20, IJ22 nozzles are sealed (capped) against ♦IJ23-IJ34, IJ36-IJ45 air. The nozzle firing is usually performed during a special clearing cycle, after first moving the print head to a cleaning station. Extra In systems which heat the ink, but do ♦Can be highly effective if ♦Requires higher drive voltage for ♦Silverbrook, power to not boil it under normal situations, the heater is adjacent to the clearing EP 0771 ink nozzle clearing can be achieved by nozzle ♦May require larger drive transistors 658 A2 and related heater over-powering the heater and boiling patent applications ink at the nozzle. Rapid The actuator is fired in rapid ♦Does not require extra drive ♦Effectiveness depends substantially ♦May be used with: succession succession. In some configurations, circuits on the print head upon the configuration of the inkjet ♦IJ01-IJ07, IJ09-IJ11 of actuator this may cause heat build-up at the ♦Can be readily controlled nozzle ♦IJ14, IJ16, IJ20, IJ22 pulses nozzle which boils the ink, clearing and initiated by digital logic ♦IJ23-IJ25, IJ27-IJ34 the nozzle. In other situations, it may ♦IJ36-IJ45 cause sufficient vibrations to dislodge clogged nozzles. Extra Where an actuator is not normally ♦A simple solution where ♦Not suitable where there is a hard ♦May be used with: power to driven to the limit of its motion, applicable limit to actuator movement ♦IJ03, IJ09, IJ16, IJ20 ink nozzle clearing may be assisted by ♦IJ23, IJ24, IJ25, IJ27 pushing providing an enhanced dnve signal ♦IJ29, IJ30, IJ31, IJ32 actuator to the actuator. ♦IJ39, IJ40, IJ41, IJ42 ♦IJ43, IJ44, IJ45 Acoustic An ultrasonic wave is applied to the ♦A high nozzle clearing ♦High implementation cost if system ♦IJ08, IJ13, IJ15, IJ17 resonance ink chamber. This wave is of an capability can be achieved does not already include an acoustic ♦IJ18, IJ19, IJ21 appropriate amplitude and frequency ♦May be implemented at actuator to cause sufficient force at the nozzle very low cost in systems to clear blockages. This is easiest to which already include achieve if the ultrasonic wave is at a acoustic actuators resonant frequency of the ink cavity. Nozzle A microfabricated plate is pushed ♦Can clear severely clogged ♦Accurate mechanical alignment is ♦Silverbrook, clearing against the nozzles. The plate has a nozzles required EP 0771 plate post for every nozzle. The array of ♦Moving parts are required 658 A2 and related posts ♦There is risk of damage to the nozzles patent applications ♦Accurate fabrication is required Ink The pressure of the ink is ♦May be effective where ♦Requires pressure pump or other ♦May be used with all pressure temporarily increased so that ink other methods cannot be pressure actuator IJ series ink jets pulse streams from all of the nozzles. This used ♦Expensive may be used in conjunction with ♦Wasteful of ink actuator energizing. Print A flexible ‘blade’ is wiped across the ♦Effective for planar print ♦Difficult to use if print head surface is ♦Many ink jet systems head print bead surface. The blade is head surfaces non-planar or very fragile wiper usually fabricated from a flexible ♦Low cost ♦Requires mechanical parts polymer, e.g. rubber or synthetic ♦Blade can wear out in high volume elastomer. print systems Separate A separate heater is provided at the ♦Can be effective where ♦Fabrication complexity ♦Can be used with ink nozzle although the normal drop e- other nozzle clearing many IJ series ink boiling ection mechanism does not require it. methods cannot be used jets heater The heaters do not require individual ♦Can be implemented at no drive circuits, as many nozzles can additional cost in some be cleared simultaneously, and no inkjet configurations imaging is required.

NOZZLE PLATE CONSTRUCTION Nozzle plate construc- Description Advantages Disadvantages Examples tion Electro- A nozzle plate is separately ♦Fabrication simplicity ♦High temperatures and pressures are ♦Hewlett Packard formed fabricated from electroformed nickel, required to bond nozzle plate Thermal Inkjet nickel and bonded to the print head chip. ♦Minimum thickness constraints ♦Differential thermal expansion Laser Individual nozzle holes are ablated ♦No masks required ♦Each hole must be individually formed ♦Canon Bubblejet ablated by an intense UV laser in a nozzle ♦Can be quite fast ♦Special equipment required ♦1988 Sercel et al., or drilled plate, which is typically a polymer ♦Some control over nozzle ♦Slow where there are many thousands SPIE, Vol. 998 polymer such as polyimide or polysulphone profile is possible of nozzles per print head Excimer Beam ♦Equipment required is ♦May produce thin burrs at exit holes Applications, pp. 76- relatively low cost 83 ♦1993 Watanabe et al., USP 5,208,604 Silicon A separate nozzle plate is ♦High accuracy is attainable ♦Two part construction ♦K. Bean, IEEE micro- micromachined from single crystal ♦High cost Transactions on machined silicon, and bonded to the print head ♦Requires precision alignment Electron Devices, wafer. ♦Nozzles may be clogged by adhesive Vol. ED-25, No. 10, 1978, pp 1185-1195 ♦Xerox 1990 Hawkin et al., USP 4,899,181 Glass Fine glass capillaries are drawn from ♦No expensive equipment ♦Very small nozzle sizes are difficult ♦1970 Zoltan capillaries glass tubing. This method has been required to form USP 3,683,212 used for making individual nozzles, ♦Simple to make single ♦Not suited for mass production but is difficult to use for bulk nozzles manufacturing of print heads with thousands of nozzles. Mono- The nozzle plate is deposited as a ♦High accuracy (<1 μm) ♦Requires sacrificial layer under the ♦Silverbrook, lithic, layer using standard VLSI deposition ♦Monolithic nozzle plate to form the nozzle EP 0771 surface techniques. Nozzles are etched in the ♦Low cost chamber 658 A2 and related micro- nozzle plate using VLSI lithography ♦Existing processes can be ♦Surface may be fragile to the touch patent applications machined and etching. used ♦IJ01, IJ02, IJ04, IJ11 using ♦IJ42, IJ17, IJ18, IJ20 VLSI ♦IJ22, IJ24, IJ27, IJ28 litho- ♦IJ29, IJ30, IJ31, IJ32 graphic ♦IJ33, IJ34, IJ36, IJ37 processes ♦IJ38, IJ39, IJ40, IJ41 ♦IJ42, IJ43, IJ44 Mono- The nozzle plate is a buried etch stop ♦High accuracy (<1 μm) ♦Requires long etch times ♦IJ03, IJ05, IJ06, IJ07 lithic, in the wafer. Nozzle chambers are ♦Monolithic ♦Requires a support wafer ♦IJ08, IJ09, IJ10, IJ13 etched etched in the front of the wafer, and ♦Low cost ♦IJ14, IJ15, IJ16, IJ19 through the wafer is thinned from the back ♦No differential expansion ♦IJ21, IJ23, IJ25, IJ26 substrate side. Nozzles are then etched in the etch stop layer. No nozzle Various methods have been tried to ♦No nozzles to become ♦Difficult to control drop position ♦Ricoh 1995 Sekiya plate eliminate the nozzles entirely, to clogged accurately et al USP 5,412,413 prevent nozzle clogging. These ♦Crosstalk problems ♦993 Hadimioglu et include thermal bubble mechanisms al EUP 550,192 and acoustic lens mechanisms ♦1993 Elrod et al EUP 572,220 Trough Each drop ejector has a trough ♦Reduced manufacturing ♦Drop firing direction is sensitive to ♦IJ35 through which a paddle moves. complexity wicking. There is no nozzle plate. ♦Monolithic Nozzle The elimination of nozzle holes and ♦No nozzles to become ♦Difficult to control drop position ♦1989 Saito et al slit replacement by a slit encompassing clogged accurately USP 4,799,068 instead of many actuator positions reduces ♦Crosstalk problems individual nozzle clogging, but increases nozzles crosstalk due to ink surface waves

DROP EJECTION DIRECTION Ejection direction Description Advantages Disadvantages Examples Edge Ink flow is along the surface of the ♦Simple construction ♦Nozzles limited to edge ♦Canon Bubblejet (‘edge chip, and ink drops are ejected from ♦No silicon etching required ♦High resolution is difficult 1979 Endo et al GB shooter’) the chip edge. ♦Good heat sinking via ♦Fast color printing requires one print patent 2,007,162 substrate head per color ♦Xerox heater-in-pit ♦Mechanically strong 1990 Hawkins et al ♦Ease of chip handing USP 4,899,181 ♦Tone-jet Surface Ink flow is along the surface of the ♦No bulk silicon etching ♦Maximum ink flow is severely ♦Hewlett-Packard TIJ (‘roof chip, and ink drops are ejected from required restricted 1982 Vaught et al shooter’) the chip surface, normal to the plane ♦Silicon can make an USP 4,490,728 of the chip. effective heat sink ♦IJ02, IJ11, IJ12, IJ20 ♦Mechanical strength ♦IJ22 Through Ink flow is through the chip, and ink ♦High ink flow ♦Requires bulk silicon etching ♦Silverbrook, chip, drops are ejected from the front ♦Suitable for pagewidth print EP 0771 forward surface of the chip. ♦High nozzle packing 658 A2 and related (‘up density therefore low ♦IJ04, IJ17, IJ18, IJ24 shooter’) manufacturing cost ♦IJ27-IJ45 Through Ink flow is through the chip, and ink ♦High ink flow ♦Requires wafer thinning ♦IJ01, IJ03, IJ05, IJ06 chip, drops are ejected from the rear ♦Suitable for pagewidth print ♦Requires special handling during ♦IJ07, IJ08, IJ09, IJ10 reverse surface of the chip. ♦High nozzle packing manufacture ♦IJ13, IJ14, IJ15, IJ16 (‘down density therefore low ♦IJ19, IJ21, IJ23, IJ25 shooter’) manufacturing cost ♦IJ26 Through Ink flow is through the actuator, ♦Suitable for piezoelectric ♦Pagewidth print heads require several ♦Epson Stylus actuator which is not fabricated as part of the print heads thousand connections to drive circuits ♦Tektronix hot melt same substrate as the drive ♦Cannot be manufactured in standard piezoelectric ink jets transistors. CMOS fabs ♦Complex assembly required

INK TYPE Ink type Description Advantages Disadvantages Examples Aqueous, Water based ink which typically ♦Environmentally friendly ♦Slow drying ♦Most existing inkjets dye contains: water, dye, surfactant, ♦No odor ♦Corrosive ♦All IJ series ink jets humectant, and biocide. ♦Bleeds on paper ♦Silverbrook EP 0771 Modern ink dyes have high water- ♦May strikethrough 658 A2 and related fastness, light fastness ♦Cockles paper patent applications Aqueous, Water based ink which typically ♦Environmentally friendly ♦Slow drying ♦IJ02, IJ04, IJ21, IJ26 pigment contains: water, pigment, surfactant, ♦No odor ♦Corrosive ♦IJ27, IJ30 humectant, and biocide. ♦Reduced bleed ♦Pigment may clog nozzles ♦Silverbrook, Pigments have an advantage in ♦Reduced wicking ♦Pigment may clog actuator EP 0771 reduced bleed, wicking and ♦Reduced strikethrough mechanisms 658 A2 and related strikethrough. ♦Cockles paper patent applications ♦Piezoelectric inklets ♦Thermal ink jets (with significant restrictions) Methyl MEK is a highly volatile solvent ♦Very fast drying ♦Odorous ♦All IJ series inkjets Ethyl used for industrial printing on ♦Prints on various substrates ♦Flammable Ketone difficult surfaces such as aluminum such as metals and plastics (MEK) cans. Alcohol Alcohol based inks can be used ♦Fast drying ♦Slight odor ♦All IJ series ink jets (ethanol, where the printer must operate at ♦Operates at sub-freezing ♦Flammable 2-butanol, temperatures below the freezing temperatures and point of water. An example of this is ♦Reduced paper cockle others) in-camera consumer photographic ♦Low cost printing. Phase The ink is solid at room temperature, ♦No drying time-ink ♦High viscosity ♦Tektronix hot melt change and is melted in the print head before instantly freezes on the ♦Printed ink typically has a ‘waxy’ feel piezoelectric ink jets (hot jetting. Hot melt inks are usually print medium ♦Printed pages may ‘block’ ♦1989 Nowak USP melt) wax based, with a melting point ♦Almost any print medium ♦Ink temperature may be above the 4,820,346 around 80° C. After jetting the ink can be used curie point of permanent magnets ♦All IJ series ink jets freezes almost instantly upon ♦No paper cockle occurs ♦Ink heaters consume power contacting the print medium or a ♦No wicking occurs ♦Long warm-up time transfer roller. ♦No bleed occurs ♦No strikethrough occurs Oil Oil based inks are extensively used ♦High solubility medium for ♦High viscosity: this is a significant ♦All IJ series ink jets in offset printing. They have some dyes limitation for use in inkjets, which advantages in improved ♦Does not cockle paper usually require a low viscosity. Some characteristics on paper (especially ♦Does not wick through short chain and multi-branched oils no wicking or cockle). Oil soluble paper have a sufficiently low viscosity. dies and pigments are required. ♦Slow drying Micro- A microemulsion is a stable, self ♦Stops ink bleed ♦Viscosity higher than water ♦All IJ series ink jets emulsion forming emulsion of oil, water, and ♦High dye solubility ♦Cost is slightly higher than water based surfactant. The characteristic drop ♦Water, oil, and amphiphilic ink size is less than 100 nm, and is soluble dies can be used ♦High surfactant concentration required determined by the preferred ♦Can stabilize pigment (around 5%) curvature of the surfactant. suspensions

Ink Jet Printing

A large number of new forms of ink jet printers have been developed to facilitate alternative ink jet technologies for the image processing and data distribution system. Various combinations of ink jet devices can be included in printer devices incorporated as part of the present invention. Australian Provisional Patent Applications relating to these ink jets which are specifically incorporated by cross reference include:

Australian Provisional Number Filing Date Title PO8066 15-Jul-97 Image Creation Method and Apparatus (IJ01) PO8072 15-Jul-97 Image Creation Method and Apparatus (IJ02) PO8040 15-Jul-97 Image Creation Method and Apparatus (IJ03) PO8071 15-Jul-97 Image Creation Method and Apparatus (IJ04) PO8047 15-Jul-97 Image Creation Method and Apparatus (IJ05) PO8035 15-Jul-97 Image Creation Method and Apparatus (IJ06) PO8044 15-Jul-97 Image Creation Method and Apparatus (IJ07) PO8063 15-Jul-97 Image Creation Method and Apparatus (IJ08) PO8057 15-Jul-97 Image Creation Method and Apparatus (IJ09) PO8056 15-Jul-97 Image Creation Method and Apparatus (IJ10) PO8069 15-Jul-97 Image Creation Method and Apparatus (IJ11) PO8049 15-Jul-97 Image Creation Method and Apparatus (IJ12) PO8036 15-Jul-97 Image Creation Method and Apparatus (IJ13) PO8048 15-Jul-97 Image Creation Method and Apparatus (IJ14) PO8070 15-Jul-97 Image Creation Method and Apparatus (IJ15) PO8067 15-Jul-97 Image Creation Method and Apparatus (IJ16) PO8001 15-Jul-97 Image Creation Method and Apparatus (IJ17) PO8038 15-Jul-97 Image Creation Method and Apparatus (IJ18) PO8033 15-Jul-97 Image Creation Method and Apparatus (IJ19) PO8002 15-Jul-97 Image Creation Method and Apparatus (IJ20) PO8068 15-Jul-97 Image Creation Method and Apparatus (IJ21) PO8062 15-Jul-97 Image Creation Method and Apparatus (IJ22) PO8034 15-Jul-97 Image Creation Method and Apparatus (IJ23) PO8039 15-Jul-97 Image Creation Method and Apparatus (IJ24) PO8041 15-Jul-97 Image Creation Method and Apparatus (IJ25) PO8004 15-Jul-97 Image Creation Method and Apparatus (IJ26) PO8037 15-Jul-97 Image Creation Method and Apparatus (IJ27) PO8043 15-Jul-97 Image Creation Method and Apparatus (IJ28) PO8042 15-Jul-97 Image Creation Method and Apparatus (IJ29) PO8064 15-Jul-97 Image Creation Method and Apparatus (IJ30) PO9389 23-Sep-97 Image Creation Method and Apparatus (IJ31) PO9391 23-Sep-97 Image Creation Method and Apparatus (IJ32) PP0888 12-Dec-97 Image Creation Method and Apparatus (IJ33) PP0891 12-Dec-97 Image Creation Method and Apparatus (IJ34) PP0890 12-Dec-97 Image Creation Method and Apparatus (IJ35) PP0873 12-Dec-97 Image Creation Method and Apparatus (IJ36) PP0993 12-Dec-97 Image Creation Method and Apparatus (IJ37) PP0890 12-Dec-97 Image Creation Method and Apparatus (IJ38) PP1398 19-Jan-98 An Image Creation Method and Apparatus (IJ39) PP2592 25-Mar-98 An Image Creation Method and Apparatus (IJ40) PP2593 25-Mar-98 Image Creation Method and Apparatus (IJ41) PP3991 9-Jun-98 Image Creation Method and Apparatus (IJ42) PP3987 9-Jun-98 Image Creation Method and Apparatus (IJ43) PP3985 9-Jun-98 Image Creation Method and Apparatus (IJ44) PP3983 9-Jun-98 Image Creation Method and Apparatus (IJ45)

Ink Jet Manufacturing

Further, the present application may utilize advanced semiconductor fabrication techniques in the construction of large arrays of ink jet printers. Suitable manufacturing techniques are described in the following Australian provisional patent specifications incorporated here by cross-reference:

Australian Provisional Number Filing Date Title PO7935 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus (IJM01) PO7936 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus (IJM02) PO7937 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus (IJM03) PO8061 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus (IJM04) PO8054 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus (IJM05) PO8065 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus (IJM06) PO8055 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus (IJM07) PO8053 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus (IJM08) PO8078 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus (IJM09) PO7933 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus (IJM10) PO7950 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus (IJM11) PO7949 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus (IJM12) PO8060 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus (IJM13) PO8059 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus (IJM14) PO8073 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus (IJM15) PO8076 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus (IJM16) PO8075 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus (IJM17) PO8079 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus (IJM18) PO8050 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus (IJM19) PO8052 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus (IJM20) PO7948 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus (IJM21) PO7951 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus (IJM22) PO8074 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus (IJM23) PO7941 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus (IJM24) PO8077 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus (IJM25) PO8058 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus (IJM26) PO8051 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus (IJM27) PO8045 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus (IJM28) PO7952 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus (IJM29) PO8046 15-Jul-97 A Method of Manufacture of an Image Creation Apparatus (IJM30) PO8503 11-Aug-97 A Method of Manufacture of an Image Creation Apparatus (IJM30a) PO9390 23-Sep-97 A Method of Manufacture of an Image Creation Apparatus (IJM31) PO9392 23-Sep-97 A Method of Manufacture of an Image Creation Apparatus (IJM32) PP0889 12-Dec-97 A Method of Manufacture of an Image Creation Apparatus (IJM35) PP0887 12-Dec-97 A Method of Manufacture of an Image Creation Apparatus (IJM36) PP0882 12-Dec-97 A Method of Manufacture of an Image Creation Apparatus (IJM37) PP0874 12-Dec-97 A Method of Manufacture of an Image Creation Apparatus (IJM38) PP1396 19-Jan-98 A Method of Manufacture of an Image Creation Apparatus (IJM39) PP2591 25-Mar-98 A Method of Manufacture of an Image Creation Apparatus (IJM41) PP3989 9-Jun-98 A Method of Manufacture of an Image Creation Apparatus (IJM40) PP3990 9-Jun-98 A Method of Manufacture of an Image Creation Apparatus (IJM42) PP3986 9-Jun-98 A Method of Manufacture of an Image Creation Apparatus (IJM43) PP3984 9-Jun-98 A Method of Manufacture of an Image Creation Apparatus (IJM44) PP3982 9-Jun-98 A Method of Manufacture of an Image Creation Apparatus (IJM45)

Fluid Supply

Further, the present application may utilize an ink delivery system to the ink jet head. Delivery systems relating to the supply of ink to a series of ink jet nozzles are described in the following Australian provisional patent specifications, the disclosure of which are hereby incorporated by cross-reference:

Australian Provisional Number Filing Date Title PO8003 15-Jul-97 Supply Method and Apparatus (F1) PO8005 15-Jul-97 Supply Method and Apparatus (F2) PO9404 23-Sep-97 A Device and Method (F3)

MEMS Technology

Further, the present application may utilize advanced semiconductor microelectromechanical techniques in the construction of large arrays of ink jet printers. Suitable microelectromechanical techniques are described in the following Australian provisional patent specifications incorporated here by cross-reference:

Australian Provisional Number Filing Date Title PO7943 15-Jul-97 A device (MEMS01) PO8006 15-Jul-97 A device (MEMS02) PO8007 15-Jul-97 A device (MEMS03) PO8008 15-Jul-97 A device (MEMS04) PO8010 15-Jul-97 A device (MEMS05) PO8011 15-Jul-97 A device (MEMS06) PO7947 15-Jul-97 A device (MEMS07) PO7945 15-Jul-97 A device (MEMS08) PO7944 15-Jul-97 A device (MEMS09) PO7946 15-Jul-97 A device (MEMS10) PO9393 23-Sep-97 A Device and Method (MEMS11) PP0875 12-Dec-97 A Device (MEMS12) PP0894 12-Dec-97 A Device and Method (MEMS13)

IR Technologies

Further, the present application may include the utilization of a disposable camera system such as those described in the following Australian provisional patent specifications incorporated here by cross-reference:

Australian Provisional Number Filing Date Title PP0895 12-Dec-97 An Image Creation Method and Apparatus (IR01) PP0870 12-Dec-97 A Device and Method (IR02) PP0869 12-Dec-97 A Device and Method (IR04) PP0887 12-Dec-97 Image Creation Method and Apparatus (IR05) PP0885 12-Dec-97 An Image Production System (IR06) PP0884 12-Dec-97 Image Creation Method and Apparatus (IR10) PP0886 12-Dec-97 Image Creation Method and Apparatus (IR12) PP0871 12-Dec-97 A Device and Method (IR13) PP0876 12-Dec-97 An Image Processing Method and Apparatus (IR14) PP0877 12-Dec-97 A Device and Method (IR16) PP0878 12-Dec-97 A Device and Method (IR17) PP0879 12-Dec-97 A Device and Method (IR18) PP0883 12-Dec-97 A Device and Method (IR19) PP0880 12-Dec-97 A Device and Method (IR20) PP0881 12-Dec-97 A Device and Method (IR21)

DotCard Technologies

Further, the present application may include the utilization of a data distribution system such as that described in the following Australian provisional patent specifications incorporated here by cross-reference:

Australian Provisional Number Filing Date Title PP2370 16-Mar-98 Data Processing Method and Apparatus (Dot01) PP2371 16-Mar-98 Data Processing Method and Apparatus (Dot02)

Artcam Technologies

Further, the present application may include the utilization of camera and data processing techniques such as an Artcam type device as described in the following Australian provisional patent specifications incorporated here by cross-reference:

Australian Provisional Number Filing Date Title PO7991 15-Jul-97 Image Processing Method and Apparatus (ART01) PO8505 11-Aug-97 Image Processing Method and Apparatus (ART01a) PO7988 15-Jul-97 Image Processing Method and Apparatus (ART02) PO7993 15-Jul-97 Image Processing Method and Apparatus (ART03) PO8012 15-Jul-97 Image Processing Method and Apparatus (ART05) PO8017 15-Jul-97 Image Processing Method and Apparatus (ART06) PO8014 15-Jul-97 Media Device (ART07) PO8025 15-Jul-97 Image Processing Method and Apparatus (ART08) PO8032 15-Jul-97 Image Processing Method and Apparatus (ART09) PO7999 15-Jul-97 Image Processing Method and Apparatus (ART10) PO7998 15-Jul-97 Image Processing Method and Apparatus (ART11) PO8031 15-Jul-97 Image Processing Method and Apparatus (ART12) PO8030 15-Jul-97 Media Device (ART13) PO8498 11-Aug-97 Image Processing Method and Apparatus (ART14) PO7997 15-Jul-97 Media Device (ART15) PO7979 15-Jul-97 Media Device (ART16) PO8015 15-Jul-97 Media Device (ART17) PO7978 15-Jul-97 Media Device (ART18) PO7982 15-Jul-97 Data Processing Method and Apparatus (ART19) PO7989 15-Jul-97 Data Processing Method and Apparatus (ART20) PO8019 15-Jul-97 Media Processing Method and Apparatus (ART21) PO7980 15-Jul-97 Image Processing Method and Apparatus (ART22) PO7942 15-Jul-97 Image Processing Method and Apparatus (ART23) PO8018 15-Jul-97 Image Processing Method and Apparatus (ART24) PO7938 15-Jul-97 Image Processing Method and Apparatus (ART25) PO8016 15-Jul-97 Image Processing Method and Apparatus (ART26) PO8024 15-Jul-97 Image Processing Method and Apparatus (ART27) PO7940 15-Jul-97 Data Processing Method and Apparatus (ART28) PO7939 15-Jul-97 Data Processing Method and Apparatus (ART29) PO8501 11-Aug-97 Image Processing Method and Apparatus (ART30) PO8500 11-Aug-97 Image Processing Method and Apparatus (ART31) PO7987 15-Jul-97 Data Processing Method and Apparatus (ART32) PO8022 15-Jul-97 Image Processing Method and Apparatus (ART33) PO8497 11-Aug-97 Image Processing Method and Apparatus (ART30) PO8029 15-Jul-97 Sensor Creation Method and Apparatus (ART36) PO7985 15-Jul-97 Data Processing Method and Apparatus (ART37) PO8020 15-Jul-97 Data Processing Method and Apparatus (ART38) PO8023 15-Jul-97 Data Processing Method and Apparatus (ART39) PO9395 23-Sep-97 Data Processing Method and Apparatus (ART4) PO8021 15-Jul-97 Data Processing Method and Apparatus (ART40) PO8504 11-Aug-97 Image Processing Method and Apparatus (ART42) PO8000 15-Jul-97 Data Processing Method and Apparatus (ART43) PO7977 15-Jul-97 Data Processing Method and Apparatus (ART44) PO7934 15-Jul-97 Data Processing Method and Apparatus (ART45) PO7990 15-Jul-97 Data Processing Method and Apparatus (ART46) PO8499 11-Aug-97 Image Processing Method and Apparatus (ART47) PO8502 11-Aug-97 Image Processing Method and Apparatus (ART48) PO7981 15-Jul-97 Data Processing Method and Apparatus (ART50) PO7986 15-Jul-97 Data Processing Method and Apparatus (ART51) PO7983 15-Jul-97 Data Processing Method and Apparatus (ART52) PO8026 15-Jul-97 Image Processing Method and Apparatus (ART53) PO8027 15-Jul-97 Image Processing Method and Apparatus (ART54) PO8028 15-Jul-97 Image Processing Method and Apparatus (ART56) PO9394 23-Sep-97 Image Processing Method and Apparatus (ART57) PO9396 23-Sep-97 Data Processing Method and Apparatus (ART58) PO9397 23-Sep-97 Data Processing Method and Apparatus (ART59) PO9398 23-Sep-97 Data Processing Method and Apparatus (ART60) PO9399 23-Sep-97 Data Processing Method and Apparatus (ART61) PO9400 23-Sep-97 Data Processing Method and Apparatus (ART62) PO9401 23-Sep-97 Data Processing Method and Apparatus (ART63) PO9402 23-Sep-97 Data Processing Method and Apparatus (ART64) PO9403 23-Sep-97 Data Processing Method and Apparatus (ART65) PO9405 23-Sep-97 Data Processing Method and Apparatus (ART66) PP0959 16-Dec-97 A Data Processing Method and Apparatus (ART68) PP1397 19-Jan-98 A Media Device (ART69) 

What is claimed is:
 1. A thermal actuator activated by means of conductive heating of an electrically conductive material, said actuator comprising: a first non-conductive strip of material attached to a substrate at a first end of said strip and adapted to apply a force to a load at a second end of said strip; a second conductive strip of material formed along one side of said first strip said second conductive strip including a first wire strip running from substantially said first end to said second end and a second wire strip running from substantially said second end to said first end, said wire strips being joined together at said second end so as to form a circuit, said wire strips being further connected to a controlled power supply at said first end such that activation of said controlled power supply causes heating of said conductive material so as to actuate said thermal actuator thereby applying a force to said load.
 2. A thermal actuator as claimed in claim 1 wherein said first strip is in a form of a coil and said second conductive material is formed along a radially inner surface of said strip.
 3. A thermal actuator as claimed in claim 1 wherein said first wire and said second wire are electrically insulated from one another by a layer of said first non-conductive material.
 4. A thermal actuator as claimed in claim 1 wherein said second conductive material comprises a material having a high Young's modulus.
 5. A thermal actuator as claimed in claim 4 wherein said first non-conductive strip is substantially thicker than said second conductive material.
 6. A thermal actuator as claimed in claim 1 wherein said substrate comprises an electronic circuitry layer of a silicon wafer.
 7. A thermal actuator as claimed in claim 1 wherein said second conductive material comprises substantially titanium diboride.
 8. A thermal actuator as claimed in claim 1 wherein said first non-conductive material comprises substantially glass.
 9. A thermal actuator as claimed in claim 1 wherein said actuator is interconnected through a slot in a nozzle chamber to a paddle type device, said nozzle chamber being filled with ink and said actuator being activated to eject ink from a port defined in one wall of said nozzle chamber.
 10. An ink jet printer having a series of ink ejection nozzle chambers, each of said nozzle chambers containing: an ink ejection port defined in one wall of the chamber for the ejection of ink therefrom; a paddle within said chamber, actuated by an actuator for the ejection of ink from said nozzle chamber via said ink ejection port; a slot defined in a second wall thereof for the communication with said paddle of an actuator device; a thermal actuator activated by means of conductive heating of an electrically conductive material, said actuator comprising: a first non-conductive strip of material attached to a substrate at a first end of said strip and adapted to apply a force to a load at a second end of said strip; a second conductive material formed along one side of said first strip said second conductive strip including a first wire strip running from substantially said first end to said second end and a second wire strip running from substantially said second end to said first end, said wire strips being joined together at said second end so as to form a circuit, said wire strips being further connected to a controlled power supply at said first end such that activation of said controlled power supply causes heating of said conductive material so as to actuate said thermal actuator thereby applying a force to said load.
 11. An ink jet printer as claimed in claim 10 wherein said nozzle chambers are formed on a silicon wafer and include a series of ink supply channels etched through said wafer for a supply of ink to said nozzle chambers. 